Separation of metals.



AND EDWARD A. .REKATE, (9F LANCASTER, NEW' YORK, ASSIGNORS 'IO UNITED STATES NICKEL COMPANY,

NEW JERSEY.

GEORGE JV. PAWEL, 0F HUDSON FALLS,

JERSEY, A CORPORATION OF lmm OF NEW BRUIISWICK, NEW' SEPARATION OF METALS.

imesoe.

No Drawing.

To all whom it may concern Be it known that we, GEORGE WV. PAWEL, a citizen of the United States, and a resident of Hudson Falls, in the county of Washington and State of New York, and EDWARD A. Rnna'rn, a citizen of the United States, and a resident of Lancaster, in the, county of Erie and State of New Yorr, have" invented an Improvement in the Separation of Metals, of which the following is a specification.

This invention relates to the separation of metals, and with regard to certain more specific features, to the preparation. of a nickel-copper matte and the separation of the nickel from the copper therein.

Among the objects of the invention may be noted the provision of a process for sepa rating nickel from othermetals, such as cop per, with which nickel often occurs in ores; the provision of an inexpensive process for extracting copper from nickel and other metals with which it is found in nature; the provision of a simple and economical method of recovering substantially all of the metal content of ores, particularly ores containing nickel, copper and precious metals, without sacrificing a high efliciency in recovery of any of the metals involved; the provision of a process of preparing a nickel-copper matte that is readily a 'ailable for various separating methods; and the provision of a process of separating metals from such a matte or from mattes of other kinds. Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly comprises the features of operation and the steps and se quence of steps which are exemplified in the following description and the scope of the application of which will be indicated in the appended claims.

In carrying out or practising this method or process, the steps employed may conveniently be referred to numerically, although it is to be understood that some of the steps may be omitted, or combined so as to take place simultaneously with other steps, without departing from the spirit of this inven- 1 tlon.

The first step is to obtain a matte from .the ordinary ores of copper, nickel or other Specification of Letters Yatent.

Application filed September 12, 1917. Serial No. 190,978.

by smelting, and the process used to effect this first step forms in itself no part of the present invention. The matte as thus obtained the crude metal combined ordinarilywith more or less sulfur, and requires to be further purified.

Second, this matte is refined to reduce its sulfur content. If the Bessemer process is uscd,-and this is preferred, as it at the same time removes the iron,a blast of air is forced through the molten matte to burn out the sulfur, and this blowing is con. tinued until the sulfur content is reduced to a suitable value, such eighteen to twenty-five per cent. by weight Third, this Bessemer matte is subjected to a continuation of the blowing-out process of the second step, to remove the excess of sulfur and reduce the sulfur content to ten or fifteen per cent, without, however, changing the sulfids in the matte to oxids or other insoluble salts. Or this third step may be dispensed with, and the fourth. step used as a substitute therefor.

In the fourth step, which is a preferred alternative for the third step, the Bessemer matte produced in the second step is diluted with about one-third of its weight of dcsulfurized copper, or preferably the nickelcopper residues (principally copper) obtained from the twelfth step, hereinafter described.

Fifth, the special matte thus obtained by steps 1, 2 and 3, or 1, 2 and 4-, as the case may be, is thoroughly ground to preferably l00-mcsh.or thereabout. This is to facilitate the intimate, rapid and thorough action of the acid hereinafter described, upon every portion of the matte. This ground matte has a sulfur content of ten or fifteen per cent, which is low in comparison with the sulfur content of eighteen to twenty-five per cent. found .in the ordinary niclzel-copper mattes. And it is to be noted that the sulfur is substantially all in the form of sulfids, which are readily attacked by sul furie acid, rather than oxids or other insoluble salts.

In the sixth step, which is'the first step succeeding the preparation of the special matte, the matte obtained in the fifth step, or for that matter, a similar matte obtained in any other way, is subjected to the action,

. up preferably diluted with about twice and this action is kept with suitable agitation for approximately twentyfour hours. The time required for this digestion may of course vary within Wide limits, depending upon such factors as the strength of acid, the properties of the matte, the extent to which the matte has been ground, the chemical com position of the matte, and the degree and type of agitation. This step of the process serves for the selective solution of the nickel by the sulfuric acid. Simultaneously with the formation of the nickel sulfate, there is a liberation of hydrogen sulfid gas, and this gas, released by the action of the acid on the of hot sulfuric acid, its weight of Water,

sulfur, saturates the solution and either precipitates the copper as sulfid, or helps to prevent the solution of the copper as sulfate, thereby formiiig the basis and means for automatic and quantitative separation of the copper from the nickel.

It is not essential that fresh acid be used in this sixth step of the process. For example, it may be found efficient to use an excess of matte and extract to saturation. the acid, or, on the other hand, the character of the matte may warrant the use of an excess of acid, so that the matte may be extracted to complete depletion of its nickel content without. using all the strength of the acid. Or, again, a combination of these two methods may be en'iployed, wherein spent acid may be used on the first extractions or fresh matte, while strong acid may be used on the final and more refractory residues; such cOunte-ncurrent arrangement is conducive to eiiiciency both in the utilization of the entire strength of the acid and in the extraction of the entire nickel con tent, and has the added advantage of employing the progressively stronger acid for attack upon the portions of the matte of increasing resistance to attack.

This sixth step results in the production of nickel sulfate in solution; and copper sulfid, together with gold, silver and other precious metals that may be in the matte, as residues. I

Seventh, if traces of copper appear in the solution, the copper may be readily preeipi tated by aspirating waste hydrogen sulfid gas through the liquid for a short time.

Eighth, the nickel may be recovered from the solution by evaporation to nickel sulfate cystals.

Ninth, the nickel sulfate crystals may be roasted i-'- the resulting oxid may be reduced ll. wry well-known manner to obtain metallic nickel. and by absorbing in Water the SO gases evolved during the roastingprocess, the greater partof the sulfuric acid employed in the sixth step maybe recori' -ercd.

Tenth, the mother liquor obtained after evaporation of the nickel sulfate in the masses eighth step, may be recovered, concentrated and used for further extractions in the sixth step. This liquid consists mainly of water, and the small amount of sulfuric'acid that has not been utilized in dissolving the nickel. Eleventh, the residues obtained in the sixth step are washed.

, Twelfth, the washed residues are refined to recover the copper, together with the gold, silver and other precious metals that may be therein. This refining process may be the same as those heretofore employed in connection with thepure copper matte, since the nickel content by this time reduced to a negligible amount, or to zero. If precious metals are present in appreciable amounts, the washed residues may be melted and converted to blister copper, which may then be treated in the ordinary manner for the recovery of its metal content. If the fourth step of the process is used, a small part of this blistercopper may be utilized as the diluent for the matte obtained in the second step.

The twelve steps above outlined will thus be seen to fall naturally into two groups, namely, steps one to five, which relate to the production of a matte that is readily attacked by sulfuric acid; and second, the treatment of such a matte, in steps six to twelve, to separate the variousmetals therein and to effect a substantially complete recovery of the amount of each metal contained in the matte. For certain purposes, the invention may be considered as comprising simply the production of the matte; for other purposes simply the treatment of a suitable matte to separate the metals therein; and from other aspects the invention comprises the combination or sequence of some or all of the steps in both of these general groups. The invention is applicable to a certain extent tothe treatment ofcobalt and other metals.

In view of the above, it is believed the various features of this invention will be clear without further elaboration, and it will be seen that with the process herein disclosed the several objects of the invention are achieved and other advantageous results attained. I

As various possible embodiments might be made of the above invention, and as various changes might be made in the embodiments above set forth, it is to be understood that all matter herein set forth is to be interpreted as illustrative and not in a limiting sense.

We claim as our invention:

1. The method of preparing a coppernickel matte, which comprises obtaining a matte from the ore, burning out the excess of sulfur but maintaining the sulfur as sulfids, diluting the resulting. matte with about one-third of its weight of desulfurized copintense The method of treating metals, which comprises obtaining a matte of low sulfur,

content, grinding the inatte, treating the ground matte with sulfuric acid, evaporating the solution and obtaining nickel there from by roast/mg and reducing, and absorbing the S0,, gases in Water developed on roasting, to recover the sulfuric acid, and

using the recovered sulfuric acid to dissolve a further portion of matte.

4:. The method of treating metals, which comprises diluting a matte with residues ob tained hereinafter, grinding the matte, treating the ground matte with sulfuric acid, Washing the residues, refining pa: of the Washed residues to obtainthe copper there in, and using part of said residues as the diluent above mentioned.

The method of treating-metals, which comprises obtaining matte in which the sulfur is combined. in a form soluble in enfuric acid, diluting the resulting matte with. about one-third of its Weight of residues obtained hereinafter, treating the matte with hot, strong sulfuric acid, Vtl} ))l"1i3lllg the solution and obtaining nickel therefrom by roasting and reducing, absorbing; the St), gasesv in water developed in roastin, to recover the sulfuric acid, refining part of the residues to obtain the copper and other metals therein, and usingpart said residues as the diluent above mentioned 6. The method of treating metals, which comprises diluting a matte with about one-- third of its. weight of desulfurized copper, grinding the matte, treating the ground matte with hot, strong sulfuric acid by a counter-current method, utilizing the hydrogen sulfid gas evolved to prevent solution of the copper, evaporating the solution and obtaining nickel therefrom, refining the. residues to obtain the copper and other metals therein, and aspirating Waste hydro gen sulfid gas through the filtered liquor to remove traces of copper the liquor.

"7. The method of treating metals, which comprises obtaining a matte from the ore, burning out the sulfur until the percentage of sulfur is con'iparativcly low, such as ten to fifteen per cent, grinding the matte about lOO-meslr treating the ground matte with sulfuric acid, evaporating the solution and obtaining nickel therefrom by roasting and rcdueii'ig. refining the residues to obtain the copper therein, and. Waste I a nickel copper matte, which &

hydrogen snlfid gas through the filtered liquor to remove traces of copper in the liquor.

8. The method of separating metals, which comprises obtaining ainatte from the ore, diluting the resulting matte with about one-third of its Weight of residues obtained hereinafter, grinding the matte to about l00-inesh, treating the ground matte with an excess of hot, strong sulfuric acid, evaporating the solution and obtaining nickel therefrom by roasting, absorbing the St), gases in water developed on roasting and reducing to recover the sulfuric acid, concentrating said acid for subsequent use with the ground matte, Washing the residues, refining part of the Washed residues to obtain the copper and other metals therein, using part of said residues as the diluent above mentioned, and aspirating Waste hydrogen suliid gas through the filtered liquor to remove traces of copper in the liquor.

9. The process comprises preparing a readily soluble matte, grinding the matte, agitating the ground matte with hot solutions of strong sulfuric acid, recovering the nickel from the solution, and recovering the sulfuric acid by absorption of the St}, gas-es in Water obtained in the recovery of the nickel, and using the recovered sulfuric acid to dissolve a further portion of Latte.

10. The process of extracting nickel which comprises preparing a readily soluble matte by diluting the original matte with residues hereinafter mentioned, treating the inattewith sulfuric acid to dissolve the nickel, I'QCOVGIiHg the nickel from the solution, recovering other metals from part of the residue, and using the ren'iainder of the residue as the diluent above mentioned. 11. The process of obtaining copper from a rich nickel-copper matte, which comprises preparing a readily soluble matte by dilution with a part of the residues hereinafter mentioned, treating the matte with sulfuric acid to dissolve the nickel component of the matte While leaving the copper component undissolved, recovering the copper in the resulting residues by any of the Well-known methods, and recovering the sulfuric acid from the liquor obtained crystallizing out the niclrel sulfate from the solution formed by the action of the sulfuric acid on the m: tte.

12 The process of obtaining copper from comprises preparing a readily soluble matte by dilution with a part of the residues hereinafter mentioned or by extensive besseincrizing, grinding the matte, treating this ground matte With hot solutions of strong sulfuric acid to dissolve the nickel component of the matte While leaving; the copper component undissolved, recovering trio copper in the resultof the well known meththe sulfuric acid from the liquid obtained by crystallizing out the nickel sulfate from the solution formed by the action of the sulfuric acid on the matte.

13. The process of extracting nickel from copper, which comprises the preparation of a readily soluble matte by dilution or by extensive bessemerizing as above described, grinding the matte, agitating the finely ground matte with hot solutions of sulfuric acid, recovering the nickel from the solution as nickel sulfate by crystallization, roasting said nickel sulfate and reducing the resulting oxid to obtain pure nickel free from copper, recovering the copper in the resulting residues, and recovering the sulfuric acid by absorption of the S0 gases in water freed on roasting the nickel sulfate, and using residues by any ods and recovering ing the recovered sulfuric acid to dissolve a further portion of matte.

14. The process of extracting nickel from emma copper from a rich nickel-copper matte, which comprises the preparation of an easily soluble matte by, dilution or by extensive bessemerizing as above described and then agitating this finely ground matte with hot solutions of strong sulfuric acid, recovering the nickel from the solution as nickel salts by crystallization from which pure nickel free from copper is obtainable by any of the Well-known methods, recovering the copper and the precious metals in the resulting residues also by any of the well-known methods, and recovering the sulfuric acid by absorption of the S0 gases in water freed on roasting the nickel sulfate crystals, and using the recovered sulfuric acid to dissolve a further portion of matte.

In testimony whereof, we have signed our names to this specification this eighth day of September, 1917.

GEORGE WV. PAVEL. EDWARD A. REKATE. 

